1 What plant has been part of America almost from the start? That plant is tobacco. Was it the first plant smoked by people? Not really, but it was the primary one.2 The main chemical in tobacco is nicotine. It is a chemical that makes people crave tobacco. It and other chemicals have strong effects on the body.3 Many of those bad chemicals come from the way tobacco is prepared. Once the leaves are harvested, they have to be cured. This is done many ways.4 Some tobacco is dried in the sun. This is how Turkish tobacco is dried.5 Other tobacco is hung up in special barns. The sun doesn't touch the leaves, but the air can move around them to dry them.6 One of the first ways to cure or dry tobacco was with the use of fire. A small, gentle fire would warm and dry the leaves. The smoke that was created from the fire would affect the later taste of the leaf. Chewing tobacco often used fire-cured leaves.7 Flavor has become important to tobacco makers. There are companies that make flavors. It is big business.8 While many people like these flavors, they have a problem. The flavors themselves are a problem. They are called AGE's (Advanced Glycation End products). They can cause cancer.